Support PointerLocation on secondary display

- Move PointerLocation from PhoneWindowManager to DisplayPolicy.
- Observe PointerLocation system setting in WindowManagerService.
- Enable only for default display or non-private display.

Bug: 126463475
Test: Enable PointerLocation, enable desktop mode, use mouse
      or touch on second display.

Change-Id: Ifbfce5a9ac4ec69530920884703445750704b5e2